Posted by Anonymous on .
Volunteers who had developed a cold within the previous 24 hours were randomized to take either zinc or placebo lozenges every 2 to 3 hours until their cold symptoms were gone. Twenty-five participants took zinc lozenges, and 23 participants took placebo lozenges. The mean overall duration of symptoms for the zinc lozenge group was x1 = 4.4 days, and the standard deviation of overall duration of symptoms was 1.6 days. For the placebo group, the mean overall duration of symptoms was x2 = 8.1 days, and the standard deviation was 1.5 days. Compute a 95% confidence interval for the difference in mean days of overall symptoms for the placebo and zinc lozenge treatments. Use the unpooled standard error and use the smaller of n1 - 1 and n2 - 1 as a conservative estimate of degrees of freedom. (Round the answers to one decimal place.)
3 to 4 days